00:00Transcription by CastingWords
00:08Take a look at the water in this glass—
00:10refreshing, hydrating, and invaluable to your survival.
00:14Before you take a sip, though,
00:16how do you know that the water inside is free from disease-causing organisms and pollutants?
00:22One out of ten people in the world can't actually be sure that their water is clean and safe to drink.
00:28Why is that?
00:31Inadequate sanitation, poor protection of drinking water sources,
00:35and improper hygiene often lead to sewage and feces-contaminated water.
00:40That's the ideal breeding ground for dangerous bacteria, viruses, and parasites.
00:46And the effects of these pathogens are staggering.
00:49Diarrheal disease from unsafe water is one of the leading causes of death around the world
00:54for children under five.
00:56And according to a UN report from 2010,
00:58microbial waterborne illnesses killed more people per year than war.
01:05Proper treatment processes, though, can address these threats.
01:09They usually have three parts—
01:11sedimentation, filtration, and disinfection.
01:14Once water has been collected in a treatment facility, it's ready for cleaning.
01:19The first step, sedimentation, just takes time.
01:23The water sits undisturbed, allowing heavier particles to sink to the bottom.
01:28Often, though, particles are just too small to be removed by sedimentation alone
01:33and need to be filtered.
01:35Gravity pulls the water downward through layers of sand that catch leftover particles in their pores,
01:41prepping the water for its final treatment—a dose of disinfectant.
01:45Chemicals, primarily forms of chlorine and ozone, are mixed in to kill off any pathogens
01:51and to disinfect pipes and storage systems.
01:55Chlorine is highly effective in destroying water's living organisms,
01:59but its use remains government-regulated because it has potentially harmful chemical byproducts.
02:05And if an imbalance of chlorine occurs during the disinfection process,
02:09it can trigger other chemical reactions.
02:12For example, levels of chlorine byproducts, like trihalomethanes,
02:16could skyrocket, leading to pipe corrosion
02:19and the release of iron, copper, and lead into drinking water.
02:25Water contamination from these and other sources, including leaching, chemical spills, and runoffs,
02:31has been linked to long-term health effects like cancer,
02:34cardiovascular and neurological diseases, and miscarriage.
02:39Unfortunately, analyzing the exact risks of chemically-contaminated water is difficult.
02:44So while it's clear that disinfectants make us safer by removing disease-causing pathogens,
02:50experts have yet to determine the full scope of how the chemical cocktail in our drinking water
02:55really impacts human health.
02:58So how can you tell whether the water you have access to,
03:02whether from a tap or otherwise, is drinkable?
03:05Firstly, too much turbidity, trace organic compounds,
03:09or high-density heavy metals like arsenic, chromium, or lead
03:14mean that the water is unsuitable for consumption.
03:17A lot of contaminants, like lead or arsenic, won't be obvious without tests,
03:22but some clues, like cloudiness, brown or yellow coloration,
03:26a foul odor, or an excessive chlorine smell,
03:29can indicate the need to investigate further.
03:32Water testing kits can go a step further
03:35and confirm the presence of many different contaminants and chemicals.
03:40With many types of contamination, there are ways of treating water
03:43that's used instead of close to its source.
03:46Point-of-use treatment has actually been around for thousands of years.
03:50Ancient Egyptians boiled away many organic contaminants with the sun's heat.
03:55And in ancient Greece, Hippocrates designed a bag that trapped bad-tasting sediments from water.
04:02Today, point-of-use processes usually involve ionization to lower mineral content.
04:07They also use adsorption filtration,
04:10where a porous material called activated carbon
04:13strains the water to remove contaminants and chemical byproducts.
04:17While it's not always an effective long-term solution,
04:20point-of-use treatment is portable, easy to install, and adaptable.
04:25And in regions where large-scale systems are unavailable
04:28or where water has been contaminated further along its journey,
04:32these systems can mean the difference between life and death.
04:36Clean water remains a precious and often scarce commodity.
04:39There are nearly 800 million of us who still don't have regular access to it.
04:44The good news is that continued developments in water treatment,
04:47both on a large and small scale, can alleviate a lot of unsafe conditions.
04:52Implementing proper systems where they're needed
04:54and paying careful attention to the ones already in place
04:57will fulfill one of the most basic of our human needs.
05:01limits.
05:07You
05:11P craziness
05:23You
